The present invention relates to x-ray imaging, and more particularly, to guidewire tracking in 2D fluoroscopic image sequences.
Coronary intervention, or coronary angioplasty, is a common medical procedure for treating heart disease. During such a coronary intervention procedure, a guidewire is inserted into a patient's blood vessels and guided to a stenosis or blockage in the coronary arteries. In image guided cardiac interventions, automatic guidewire tracking has important applications. Since a low dose of radiation and contrast materials is desirable during interventions, fluoroscopic images captured during interventions typically have low image quality. This leads to low visibility of vessels, catheters, and guidewires during intervention procedures. Automatic guidewire tracking can help to improve the visibility of a guidewire, and assist clinicians in obtaining high precision in image-guided interventions.
Guidewire tracking in fluoroscopic image sequences is challenging. Guidewires are thin and typically have low visibility in fluoroscopic images, which typically have poor image quality due to the low dose of radiation used in interventional imaging. FIG. 1 illustrates guidewires in exemplary fluoroscopic images 102, 104, 106, and 108. Sometimes segments of guidewires are barley visible in noisy images. Such weak and thin guidewire structures in noisy images make robust tracking difficult. Guidewires also exhibit large variations in their appearances, shapes, and motions. The shape deformation of a guidewire is mainly dues to a patient's breathing and cardiac motions in 3D, but such 3D motions are complicated when being projected onto a 2D image space. Furthermore, there may exist other wire-like structures, such as guiding catheters and ribs, in fluoroscopic images.
Since a guidewire is thin, tracking methods that use regional features, such as holistic intensity, textures, and color histogram, cannot track a guidewire well. Active contour and level set based methods rely heavily on intensity edges, so they are easily attracted to image noise and other wire-like structures in fluoroscopic images. Furthermore, active contour and level set based methods can only track closed contour, while the guidewire is an open curve. Considering the noise level in typical fluoroscopic images, existing methods cannot deliver desired speed, accuracy, and robustness for coronary interventions. Accordingly, a guidewire tracking method that is fast, robust, and accurate is desirable.